> For the complete documentation index, see [llms.txt](https://docs.verifone.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.verifone.com/support-nordics/v400m/errors/mobile-data-is-not-working.md).

# Mobile Data Is Not Working

What to do when mobile data (4G) isn't working on your V400M — check the battery, settings, and SIM card.

{% hint style="info" %}
**Use this page when** your V400M won't connect using **mobile data (4G)**.
{% endhint %}

<details>

<summary>Keywords</summary>

Also called: mobile data not working, 4G not working, GPRS not working, no mobile signal, SIM not working, can't connect on mobile data. Search terms: mobile data, 4G, GPRS, SIM, APN, battery, network interface, internal error.

</details>

## Symptoms

You may see one or more of the following:

* The terminal won't connect using mobile data.
* Payments fail when the terminal is using mobile data.
* **Start Network Interface** fails, or the terminal shows **"FAILED: Internal error"**.

**Why this happens:** mobile data can stop working if the battery is low, the mobile data settings are wrong, the SIM card has moved out of place, or there's a mobile network problem in your area.

## Before you start

{% hint style="warning" %}
**Mobile data doesn't work if the battery is below 30%.** Charge the terminal to above 30% before you start.
{% endhint %}

It's also worth checking whether your mobile network provider has reported any outages in your area.

## Resolution

{% stepper %}
{% step %}

### Check the battery level

Make sure the battery is **above 30%**. If it's lower, charge the terminal and try again.

✅ **Mobile data works — stop here.** ❌ **Still not working — continue to Step 2.**
{% endstep %}

{% step %}

### Check the mobile data settings

Start the network interface and check the SIM slot and APN settings — see [How to Check Mobile Data Configuration](/support-nordics/v400m/how-tos/how-to-check-mobile-data-configuration.md).

✅ **Status shows "Successful" — stop here.** ❌ **Still failing — continue to Step 3.**
{% endstep %}

{% step %}

### Check the SIM card is in place

Turn the terminal off, take out the battery, and check the SIM card behind it is sitting straight and pushed fully into its slot — see Step 5 of [How to Check Mobile Data Configuration](/support-nordics/v400m/how-tos/how-to-check-mobile-data-configuration.md).
{% endstep %}

{% step %}

### Restart the terminal

Restart the terminal — see [How to Reboot the Terminal](/support-nordics/v400m/how-tos/how-to-reboot-the-terminal.md) — then try a test transaction.

✅ **Transaction works — stop here.** ❌ **Still not working — continue to Step 5.**
{% endstep %}

{% step %}

### Check whether the battery could be the cause

If you still see **"FAILED: Internal error"**, the battery may be worn out. Check:

* Does the terminal **switch off quickly** when it isn't plugged in to charge?
* Can the terminal **connect to Wi-Fi** — see [How to Set Up Wi-Fi](/support-nordics/v400m/how-tos/how-to-set-up-wi-fi.md)?

Let Verifone Support know your answers in the next step.
{% endstep %}

{% step %}

### Contact Verifone Support

If mobile data still isn't working, <mark style="color:red;">contact Verifone Support</mark>. We'll help you work out whether the terminal needs a new battery.
{% endstep %}
{% endstepper %}

**If mobile data is working.** Your terminal is ready to use.

**If it still isn't working.** Contact Support below.

## Still not working?

{% hint style="info" %}
**Still need help? Contact Verifone Support.**

If the steps above haven't resolved the issue, <mark style="color:red;">contact Verifone Support</mark>. Tell us the troubleshooting steps you've already tried — it helps us get you to the right support faster.
{% endhint %}


---

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